Renewable electrical energy sources such as wind and solar naturally furnish DC power. Meanwhile, many electronic devices for the home, lab and other environments are designed to accept AC power and internally convert to DC. The requisite power conversion electronics add complexity and dissipate power. It is therefore desirable to enable such devices to directly utilize DC power furnished by renewable sources. Adoption of power plugs having a new physical configuration is unlikely to be viable; thus it is desirable to adapt standard AC plugs and receptacles to flexibly furnish power from either AC or DC power sources as appropriate for the devices of interest.